High-order directional microphone diaphragm

Abstract

The invention features a miniature, second-order, microcrystalline silicon microphone diaphragm formed using silicon microfabrication techniques. The diaphragm is composed of two or more rigid diaphragm elements hinged to one another providing second- or higher-order response depending on the number of diaphragm elements used. The response of the differential diaphragm has a response that is highly dependent on the direction of the incident sound. The diaphragms are useful for constructing highly innovative microphones that have far greater directionality, better sensitivity, wider frequency response, and lower noise than is achievable with current technology.

1. A miniature differential microphone, comprising:
 at least a pair of substantially rigid diaphragm segments each having two opposing surfaces and two opposing edges, said opposing edges being substantially parallel to one another, at least one of said two opposing edges of each of said at least a pair of diaphragm segments defining a hinge edge, each of said at least a pair of diaphragm segments being disposed adjacent one another with one of said at least one hinge edge thereof being aligned proximate and substantially parallel to said at least one hinge edge of another of said at least a pair of diaphragm segments; 
 a first hinge fixedly attached to each adjacent one of said at least one hinge edge of each adjacent pair of said at least a pair of diaphragm segments disposed to flexibly join adjacent ones of said at least one hinge edges; 
 a second hinge located beneath a lower one of said two opposing faces and positioned substantially centrally thereupon and substantially parallel to each of said two hinge edges. 
 
   
   
     2. The miniature differential microphone as recited in  claim 1 , wherein said at least two diaphragm segments are substantially identical to one another. 
   
   
     3. The miniature differential microphone as recited in  claim 1 , wherein each of said at least two diaphragm segments are dimensioned in the range of approximately 1 mm×2 mm and each have a thickness in the range of approximately 2 •m. 
   
   
     4. The miniature differential microphone as recited in  claim 1 , wherein each of said at least two diaphragm segments comprise polycrystalline silicon. 
   
   
     5. The miniature differential microphone as recited in  claim 4 , wherein each of said at least two diaphragm segments are constructed using silicon microfabrication techniques.